1. Field of the Invention
The present invention relates to a flow control apparatus for controlling the flow rate of a gas or a liquid supplied into a processing apparatus such as an annealing apparatus for a semiconductor wafer and to a fluid supply mechanism and a processing apparatus which use the flow control apparatus.
2. Description of the Related Art
In a conventional gas supply mechanism for supplying a predetermined gas at a predetermined flow rate, a flow control apparatus, i.e., a so-called mass-flow controller, comprising a flow-rate detection sensor for detecting a gas flow rate, a gas flow adjustment mechanism, and a control mechanism for controlling the gas flow adjustment mechanism in accordance with a flow-rate detection signal from the flow-rate detection sensor is popularly used.
For example, in the manufacturing process of a semiconductor device, the mass-flow controller described above is used in a gas supply mechanism used in a heat treatment apparatus for performing processing such as film formation to a target object such as a semiconductor wafer. This mass-flow controller is arranged midway along each gas supply pipe for connecting a process vessel for performing processing such as film formation to a semiconductor wafer to gas sources for a plurality of reaction gases or carrier gases. The mass-flow controller and other piping machines such as valves and filters arranged in each gas supply pipe form a gas supply mechanism. Since the mass-flow controller serves as the principal part of the gas supply mechanism, this mechanism must be periodically subjected to inspection and maintenance more frequently than other machines.
However, in a conventional mass-flow controller, since a gas supply pipe is directly connected to a fluid inlet and a fluid outlet, the degree of freedom of piping is low, and only a planer piping structure is obtained. In addition, since the gas supply mechanism is increased in size, when maintenance of machines on the process vessel side is considered, the gas supply mechanism must be arranged apart from a process vessel. For this reason, an area occupied by the entire processing apparatus is disadvantageously increased.
Since, in addition to the low degree of freedom of piping and the planer piping structure, piping is also performed using a joint, the piping structure is complicated. Therefore, maintenance and inspection of the mass-flow controller are disadvantageously cumbersome.